When Someone Is Lying To You, Does Their Pupil Size Get Smaller?

Hi...I think when someone lies, their eyes will look to the right as this translates to the left part of the brain where imagination occur (if they are telling the truth..they will look to their left as this translates to the right side of the brain where memories are stored, their pupils do get smaller, their cheeks will turn red, they will not be able to look you in the eye, posture will not be direct, their voice will probably raise in pitch and they probably will not be able to tell the same lie again as it is a made up story and will change over time...those who lie on a regular basis should be avoided...knowing when someone lies is always to your benefit...I personally do not think you should let on at first, at least, to the person that you know they are lying....Dublin, Ohio

I would say no because someone(not going to say) tells me that they know if I'm lying from my pupils getting smaller but really I'm telling the truth and take it from a girl who knows and has had experience

This would not be an indicator to use on its own, as pupil's will decrease in size as psychological comfort decreases...and if you're grilling him on his fidelity, he will surely be uncomfortable. I have found movement of the head to be the most reliable indicator in my work in law enforcement. Away from you or toward the exit is a key to watch for.

I would say yes. It's hard to tell a lie without knowing the individual person. Everyone shows nervous in different ways. Hands and the way they move and are placed can say much. But the pupils changing size indicates his vision was going through a change. Perhaps he was no longer looking at you but in himself for an answer, and his eyes moved out of focus for a moment. In short, if he had to hesitate and search for an answer, he definitely is hiding something.

The pupil dilates in extreme physical situations (e.g.,fear) or contact of a sensory nerve, such as pain.  The Task-evoked pupillary response is the tendency of pupils to dilate slightly in response to loads on working memory, increased attention, sensory discrimination, or other cognitive loads.  According to Wikipedia  Maybe you got his attention!

The are  too many indicaters to tell if he was lying
you need to look at their hand and see how they were moving, where his eyes were at(in the eyes mean he's trying to make you believe he isn't) and not only thos but you need to have a baseline on the person to tell when they are or are not lying.
Basicly if you rrally want to know you need to watch lie to me or start reading any thing from dr. Paul Ekman